Surface smoothing arrangement

ABSTRACT

A workpiece having opposite faces is mounted for rotation about a first axis transverse to these faces. A pair of smoothing rolls are located on opposite sides of the workpiece in pressure engagement with the faces thereof and rotatable about a second axis which are inclined at respective small angles to the same. They are located in a common plane perpendicular to the faces. The rolls are supported for rotation about the second axis and are pressed against the faces of the workpiece. The rolls, the arrangement supporting them and the arrangement for pressing them against the faces of the workpiece can be jointly pivoted about a third axis extending intermediate and parallel to the faces midway between the points of contact between the rolls and the faces through an imaginary line connecting these points of contact.

United States Patent [191 Kunze SURFACE SMOOTHING ARRANGEMENT [75] Inventor: Bernhard Kunze,Erkelenz,

Germany [73] Assignee: Wilhelm Hengenscheidt GmbH,

Erkelenz, Germany 22 Filed: Sept. 10, 1973 211 Appl. No.: 396,117

[52] US. Cl 29/90 R [51] Int. Cl. B2lc 37/30 [58] Field of Search 29/90 R [56] References Cited UNITED STATES PATENTS 2,734,255 2/1956 Tack 29/90 R 2,915,809 12/1959 2,959,841 11/1960 Judge, Sr. 29/90 R 3,448,504 6/1969 Dombrowski et a1. 29/90 R Feb. 18, 1975 Primary Examinerl-larrison L. Hinson Attorney, Agent, or Firm-Michael S. Striker [57] ABSTRACT A workpiece having opposite faces is mounted for rotation about a first axis transverse to these faces. A pair of smoothing rolls are located on opposite sides of the workpiece in pressure engagement with the faces thereof and rotatable about a second axis which are inclined at respective small angles to the same. They are located in a common plane perpendicular to the faces. The rolls are supported for rotation about the second axis and are pressed against the faces of the workpiece. The rolls, the arrangement supporting them and the arrangement for pressing them against the faces of the workpiece can be jointly pivoted about a third axis extending intermediate and parallel to the faces midway between the points of contact between the rolls and the faces through an imaginary line connecting these points of contact.

5 Claims, 8 Drawing Figures SHEET 10F 1,

WJENKD FEB I 81975 Fig.7

PATENTEU 3, 866,281

' SHEET 3 or 4 PHEHIEB FEB] 81975 SHEET u 0F 4 Fig. 4

1 SURFACE SMOOTI-IING ARRANGEMENT BACKGROUND OF THE INVENTION The present invention relates generally to the smoothing of workpiece surfaces, and'more particularly to an arrangement of surface smoothing purposes. Still more particularly, the invention relates to a surface smoothing arrangement for smoothing the surface of a workpiece by a roll which rolls on a surface of the workpiece and is pressed against the same.

It is known from the prior art to exert pressure upon the surface of the workpiece with a roll which is pressed against this surface. When the pressure is sufficiently high, the surface layer of the workpiece material is permanently deformed because the material is stretched beyond the yield point. Minute projections of the surface layer yield under the pressure and flow into the similarly minute valleys of the surface to fill the same; as a result the surface becomes leveled, extremely smooth and highly glossy.

An arrangement for smoothing planar surfaces of a workpiece, in the manner and for the purposes outlined above, is known from US. Pat. No. 3,448,504 of Theodor Dombrowski and Bernhard Kunze. In that arrangement two slanted smoothing rolls are pressed from opposite sides into rolling contact with a rotating workpiece and are transported in radial direction of the workpiece. This causes the desired plastic deformation of the surface layer of the workpiece material, the contact between the workpiece surface or surfaces and the rolls having a dropped pressure area which is so small that a very high specific pressure can be produced by comparatively small pressure forces acting on the smoothing rolls for the purpose of pressing the same against the workpiece surfaces. This is favorable insofar as possible deformation of the workpiece is concerned, and bending forces acting on the workpiece are avoided by symmetrically positioning the smoothing rolls so that opposite pressure areas register and the pressure supplied by the smoothing rolls compensate each other.

The workpieces which are to be so smoothed are carefully prepared in advance and have a macrogeomtrically acceptable surface and configurations. However, it has been found that both the internal stresses in the workpiece resulting from shaping of the workpiece plan as well as the surface stresses which result from the preliminary preparation of the workpiece are released during the smoothing via the rollers of the prior-art construction, so that the planar surfaces 7 which originally extend normal to the axis of rotation about which the workpiece is turned, tend to become deformed, in such a manner that after the rolling they include an angle with this axis of rotation, resembling essentially a bowl-shaped configuration with conical edge. The blanks from which the workpieces are made are frequently of cast iron, particularly if the workpiece is the rotor of a motor vehicle'disc brake, and uneven cooling after casting and uneven removal of the casting skin will cause the aforementioned internal stresses. Again, the surface stresses are the result of the preliminary treatment to which the blanks are subjected prior to rolling, which preliminary treatment is usually a milling operation in which the surface stresses are created which become added to the existing internal stresses. These surface stresses predominantly are the result of a variation in the milling speed during milling to obtain planar surfaces, as the milling cutter moves from the outer edge inwardly, or from the center of the respective surface outwardly.

When the opposite surfaces of the workpiece are uniformly subjected to the high specific roller pressure which deforms the material of the workpiece at the surface layer past the yield point, these stresses are released and as a result the workpiece becomes deformed in the manner discussed earlier, so that it is no longer useable, especially as the rotor of a disc brake.

SUMMARY OF THE INVENTION It is, accordingly, an object of the present invention to overcome the disadvantages of the prior art.

More particularly, it is an object of the present invention to provide an improved arrangement for surface smoothing purposes which does not possess the aforementioned disadvantages.

In keeping with these objects and with others which will become apparent hereafter, one feature of the invention resides in an arrangement which, briefly stated, comprises mounting means for mounting a workpiece having opposite faces for rotation about a first axis transverse to said faces. A pair of smoothing rolls are located on opposite sides of the workpiece in pressure engagement with these faces and rotatable about a second axes which are inclined at respective small angles to the same and located ina common plane perpendicular to the faces. Support means support the rolls for rotation about the second axes. Pressure means presses the rolls against the faces. Means is provided for pivoting the rolls, support means and pressure means jointly about a third axis which extends intermediate and parallel to the faces midway between the points of contact between the rolls and the faces through an imaginary line connecting said points. Measuring means measures the the extent of such pivoting.

The present invention avoids the disadvantages of the prior art, based upon the following considerations:

Given uniform roller pressure, the surface pressure is the greater the smaller the area of contact between the rollers and the workpiece will be. Two parallel faces of the workpiece, which are subjected to the same conditions that is substantially point-shaped specific surface pressure will behave identically and will permit the stresses to equalize and to deform the workpiece within the range of plastification.

Circumstances are different, however, when the specific roller pressure of the two opposite rollers is not identical. In that case, the surface upon which the higher specific roller pressure is exerted, is caused to stretch with respect to the other surface so that changing the surface pressures can result in a change of the workpiece shape.

This change is accommodated in the manner outlined above, namely by pivoting the rolls, support means and pressure means jointly about the aforementioned third axis so that the angle of inclination of the one roller with reference to the associated surface of the workpiece is steeper than the angle of inclination of the other roller with reference to the workpiece surface with which it cooperates. In other words, as the angle of inclination of one roller becomes steeper, the angle of inclination of the other roller becomes flatter at the same time. This means that the contact area between the respective workpiece surfaces and the associated rollers is changed at the same time. The roller having the steeper angle of inclination has a'smaller contact area and produces a higher specific pressure, whereas the roller having the smaller angle has a larger contact area and produces a lesser specific pressure. Thus, if the workpiece has previously become deformed so as to be essentially ball-shaped or concave on the side of one roller, a pivoting causing the roller at the other side to have a steeper angle of inclination with respect to its associated surface and to exert a higher surface pressure, causes this deformation effect to be counteracted and the workpiece to be deformed in the opposite sense until it becomes again planar.

The pivoting can be automatically controlled by means of one of the known commercially available control devices which scan the workpiece without having contact therewith (pneumatically) during the rolling operation and which detect and transmit any deformations of the workpiece via the pneumatic differential pressure and an electrical comparator to a hydraulic cylinder and piston unit which effects the necessary pivoting of the rolls. The pivoting can be effected by means of a hydraulic device having a chamber in which a three-part piston is displaceable, the latter having a larger diameter center portion and two smallerdiameter end portions, on each of which sleeves can shift axially whose diameter is greater than that of the center portion of the pistonand which can abut against an abutment in the interior of thedevice, the length of which abutment corresponds to the length of the center portion of the piston.

Details will be discussed subsequently.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a front view, in a somewhat diagrammatic ilustration, of an arrangement according to the present DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing the drawing in detail, and referring firstly to FIGS. 1 3, it will be seen that a workpiece 3 is provided having two oppositely directed surfaces each of which is engaged by one of the two surface smoothing rollers l and 2. These rollers are also supported by supporting rollers 4 and 5, respectively, which are mounted on arms 6 and 7 which also guide the rollers l and 2. The arms 6 and 7 are pivoted together at 10, and are also connected by a drive arrangement 11 which can pivot both arms 6 and 7 and thus vary the lateral spacing of the rollers l and 2 from one another.

A base plate 12 is provided on which the arms 6 and 7 are supported by members 8 and 9, respectively. The members 8 and 9 can be pivoted about a bolt 13 on a carriage 14. The pivot axis defined by the bolt 13 is located in the center plane between the points of contact of the rollers l and 2 with the surfaces of the workpiece 3, and the vertical line connecting these two points of contact. The carriage I4 is moved by a hydraulic drive 15 which is arranged in the support 16. j

The workpiece 3 is held in an apparatus which can turn it and which maintains it against axial movement. On the tail stock end 17 there is mounted for displacement a pneumatic measuring device 18 which is known in the art and commercially available Prospect Fa. Etamic No. E6802D, particular FIG. III. This type of device produces between itself and the juxtaposed surface of the workpiece 3 an aircushion. In addition, it is provided at two locations which are spaced as far apart from one another as possible, with nozzles 19, the differential pressure of which is transmitted via electrical contacts to a hydraulic control element 20. Thus, depending upon the differential pressures which are sensed by the nozzles 19, the device 18 determines changes in the configuration of the workpiece without having to come in contacttherewith, and at the same time controls changes in the inclination of the rolls 1 and 2 with reference to the workpiece 3. Reference numeral 40 identifies the supply of compressed air, reference numeral 41 the device which measures the differential pressure, and reference numeral 42 the electrical comparator which is also known from the art and which controls the hydraulic unit20 Prospect Fa. Etamic No. E6802D, particular FIG. III.

The latter is connected via the conduits 21 and 22 with a hydraulic unit 26, in which there is located a piston 23, having a larger-diameter center portion and two smaller-diameter end portions. On each of the end portions there is provided a sleeve, identified with reference numerals 24 and 25, respectively. These sleeves are pressed against corresponding abutments in the unit 26. When pressure fluid is admitted at the righthand side, then the appropriate end face of the piston 23 and the end face of the sleeve 25 are subjected to pressure by thepressure fluid. The sleeve 25 cannot move in the unit 26, because it is pressed against an abutment as illustrated. The larger-diameter center portion 28 of the piston 23, however, presses against the sleeve 24 which shifts the same towards the left in FIG. 3. When, on the other hand, pressure fluid is admitted at the left-hand side of the unit 26, then it acts upon the left-hand end face of the piston 23 and the sleeve 24. Because the combined surface end faces of the left-hand end of the piston 23 and of the sleeve 245 are greater than the surface area at the right-hand end of the piston 23 (the surface area of the sleeve 25 must be neglected because the sleeve 25 cannot move and therefore cannot contribute towards the force with which the pressure fluid-admitted at the right-hand end of unit 26 shifts the piston 23 towards the left) piston 23 and sleeve 24 are now displaced towards the right until the sleeve 24 moves against its associated abutment and the piston 23 is in the illustrated center position. This is maintained until the pressure of fluid at the left-hand side of the unit 26 increases, in which case, the regulating movement is repeated, with the piston 23 and the sleeve 25 first moving towards the right and then moving back towards the center until the piston 23 is centered. If the fluid pressure at both ends of the unit 26 is identical, then piston 23 remains in its center position.

An arm 29 is fast with the center portion 28 of the piston 23, extending through a slot 30, in the housing of the unit 26 and having exteriorly of the latter a ball 31 which is tiltably accommodated in a socket 32 provided on a slide 33 which is capable of performing a slight axial movement, being guided on the plate 12.

As the drawing shows, the plate 12 can be pivoted about the bolt 13. If, now, the device 18 detects a change in the configuration of the workpiece 3, and actuates the unit 20, so that compressed pressure fluid is caused to enter into one end of the unit 26, then the resulting movement of the piston 23 is transmitted via arm 29 and ball 31 to the plate 12, causing the same to be pivoted about the axis 13 of the bolt 13. This, in turn, causes the angle of inclination of both of the rollers l and 2 with respect to the disc-shaped workpiece to become altered at the same time, that is the angle of inclination of one of the rollers relative to the workpiece 3 increases, and at the same time the angle of inclination of the other roller decreases as the rollers are pivoted about the axis 13'. This, in turn, means that the contact area between the roller whose angle of inclination increases will become smaller, and the contact area of the roller whose angle of inclination decreases will become larger. The smaller surface area results in the exertion of a higher specific roller pressure upon the surface, and thus causes a more substantial plastic deformation of the workpiece, so that this side of the disc-shaped workpiece 3 is stretched, that is the workpiece is returned towards planar condition.

FIG. 4 shows the ideal configuration of the workpiece, that is the configuration in which the workpiece is not at all deformed. FIG. 5 shows the workpiece 3 to be deformed to a bowl-shaped configuration, as a result of the release of stresses in the workpiece, which release has been brought about by the conventional surface-smoothing operation by engagement of the workpiece with rollers from the opposite sides, with the rollers being identified with reference numerals 50 and 51, respectively. To counteract this undesired deformation, the rolls 50 and 51 have been pivoted in FIG. 1 towards the left from the position illustrated in FIG. 4, so that the left-hand surface of the workpiece 3 has only a small area of contact with the roll 50, whereas the right-hand surface has a relatively large area of contact with the roll 51. This counteracts the deformation of the workpiece and will return the workpiece to the configuration shown in FIG. 4.

FIG. 6 shows another undesired deformation of the workpiece, which is in the opposite direction from that shown in FIG. 5. The reason is again the release of stresses in the workpiece during the rolling smoothing of the workpiece surfaces. In FIG. 6 it is the right-hand surface of the workpiece 3 which must be stretched and deformed, so that the rolls S0 and 51 have been pivoted in the opposite direction to that of FIG. 5, in order for a small area of contact to exist between the roll 51 and the associated surface, and a large area of contact between the roll 50 and the associated surface.

FIG. 7 shows the form of the contact area between the rolls and the workpiece. FIG. 7 shows the short surface area 34 over which the workpiece 3 is contacted by the rolls 50 and 51 in FIG. 5 and FIG. 6, respectively. This produces a high specific roller pressure upon the workpiece and the designation 10 in FIG. 7 is intended to indicate a length of the contact area 34 of for instance 10 mm. Evidently, that this length can vary and is to be considered exemplary only. FIG. 8 shows the surface area 35, having for instance a length of 14 mm, over which the roll 51 in FIG. 5 or the roll 50 in FIG. 6 will engage the workpiece 3, and wherein a small specific roller pressure will be exerted upon the workpiece 3. It should be noted that FIG. 7 identifies the location of the surface area 34 on the workpiece as seen in the direction of the arrow A in FIG. 5, and FIG. 8 identifies the location of the surface area 35 on the workpiece 3 as seen in the direction of the arrow B of FIG. 6.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions, differing from the types described above.

While the invention has been illustrated and described as embodied in a surface smoothing arrangement, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

1. Surface smoothing arrangement, comprising mounting means for mounting a workpiece having opposite faces for rotation about a first axis transverse to said faces; a pair of smoothing rolls located on opposite sides of said workpiece in pressure-engagement with said faces and rotatable about second axes which are inclined at respective small angles to the same, and located in a common plane perpendicular to said faces; support means supporting said rolls for rotation about said second axes; pressure means for pressing said rolls against said faces; means for pivoting said rolls, support means, and pressure means jointly about a third axis which extends intermediate and parallel to said faces midway between points of contact between said rolls and said faces through an imaginary line connecting said points of contact and which also extends normal to said common plane; and measuring means for measuring any curvature of said faces and for correspondingly automatically actuating said pivoting means to the extent necessary for said rolls to smooth and remove such curvature.

2. Surface smoothing arrangement, comprising mounting means for mounting a workpiece having opposite faces for rotation about a first axis transverse to said faces; a pair of smoothing rolls located on opposite sides of said workpiece in pressure-engagement with said faces and rotatable about second axes which are inclined at respective small angles to the same,'and located in a common plane perpendicular to said faces; support means supporting said rolls for rotation about said second axes; pressure means for pressing said rolls against said faces; means for pivoting said rolls, support means, and pressure means jointly about a third axis which extends intermediate and parallel to said faces midway between points of contact between said rolls and said faces through an imaginary line connecting said points of contact, said means for pivoting comprising a hydraulic unit having a cylinder, a piston axially shiftable in said cylinder and having a larger-diameter center portion and two smaller-diameter end portions, a pair of sleeves surrounding and axially slidable on the respective end portions and having a diameter greater than that of said center portion, said sleeves being engageable with an abutment of said unit the length of which corresponds to the length of said center portion and a lever mounted on said center portion and extending through a slot of said cylinder to the exterior thereof; control means for controlling the pivoting in dependence upon the shape of the workpiece; and

measuring means for measuring the extent of such pivoting.

3. Surface smoothing arrangement, comprising mounting means for mounting a workpiece having opposite faces for rotation about a first axis transverse to said faces; a pair of smoothing rolls located on opposite sides of said workpiece in pressure-engagement with said faces and rotatable about second axes which are inclined at respective small angles to the same, and located in a common plane perpendicular to said faces; support means supporting said rolls for rotation about said second axes; pressure means for pressing said rolls against said faces; means for pivoting said rolls, support means, and pressure means jointly about a third axis which extends intermediate and parallel to said faces midway between points of contact between said rolls and said faces through an imaginary line connecting said points of contact, said means for pivoting comprising a hydraulic unit having a cylinder. a piston axially shiftable in said cylinder and having a larger-diameter center portion and two smaller-diameter end portions, a pair of sleeves surrounding and axially slidable on the respective end portions and having a diameter greater than that of said center portion, said sleeves being engageable with an abutment of said unit the length of which corresponds to the length of said center portion and a lever mounted on said center portion and extending through a slot of said cylinder to the exterior thereof; and measuring means for measuring the extent of such pivoting.

4. An arrangement as defined in claim 3, wherein said support means comprises a table which is pivotable about said third axis; and said lever having a ball member exteriorly of said cylinder and engaging in a mating socket of said table. 5. An arrangement as defined in claim 4; and further comprising adjustable abutments for adjustably limiting the axial shifting of said piston in said cylinder.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,866,281

DATE I February 18, 1975 INVENTOR(S) I Bernhard Kunze It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the cover sheet [73] the name of the Assignee should read WILHELM HEGENSCHEIDT GMBH Signed and Sealed this second D 3y Of September 19 75 [SEAL] Arrest.

RUTH C. MASON C. MARSHALL DANN Alrestr'ng Officer (mnmissruner uj'larents and Trademarks 

1. Surface smoothing arrangement, comprising mounting means for mounting a workpiece having opposite faces for rotation about a first axis transverse to said faces; a pair of smoothing rolls located on opposite sides of said workpiece in pressureengagement with said faces and rotatable about second axes which are inclined at respective small angles to the same, and located in a common plane perpendicular to said faces; support means supporting said rolls for rotation about said second axes; pressure means for pressing said rolls against said faces; means for pivoting said rolls, support means, and pressure means jointly about a third axis which extends intermediate and parallel to said faces midway between points of contact between said rolls and said faces through an imaginary line connecting said points of contact and which also extends normal to said common plane; and measuring means for measuring any curvature of said faces and for correspondingly automatically actuating said pivoting means to the extent necessary for said rolls to smooth and remove such curvature.
 2. Surface smoothing arrangement, comprising mounting means for mounting a workpiece having opposite faces for rotation about a first axis transverse to said faces; a pair of smoothing rolls located on opposite sides of said workpiece in pressure-engagement with said faces and rotatable about second axes which are inclined at respective small angles to the same, and located in a common plane perpendicular to said faces; support means supporting said rolls for rotation about said second axes; pressure means for pressing said rolls against said faces; means for pivoting said rolls, support means, and pressure means jointly about a third axis which extends intermediate and parallel to said faces midway between points of contact between said rolls and said faces through an imaginary line connecting said points of contact, said means for pivoting comprising a hydraulic unit having a cylinder, a piston axially shiftable in said cylinder and having a larger-diameter center portion and two smaller-diameter end portions, a pair of sleeves surrounding and axially slidable on the respective end portions and having a diameter greater than that of said center portion, said sleeves being engageable with an abutment of said unit the length of which corresponds to the length of said center portion and a lever mounted on said center portion and extending through a slot of said cylinder to the exterior thereof; control means for controlling the pivoting in dependence upon the shape of the workpiece; and measuring means for measuring the extent of such pivoting.
 3. Surface smoothing arrangement, comprising mounting means for mounting a workpiece having opposite faces for rotation about a first axis transverse to said faces; a pair of smoothing rolls located on opposite sides of said workpiece in pressure-engagement with said faces and rotatable about second axes which are inclined at respective small angles to the same, and located in a common plane perpendicular to said faces; support means supporting said rolls for rotation about said second axes; pressure means for pressing said rolls against said faces; means for pivoting said rolls, support means, and pressure means jointly about a third axis which extends intermediate and parallel to said faces midway between points of contact between said rolls and said faces through an imaginary line connecting said points of contact, said means for pivoting comprising a hydraulic unit having a cylinder, a piston axially shiftable in said cylinder and having a larger-diameter center portion and two smaller-diameter end portions, a pair of sleeves surrounding and axially slidable on the respective end portions and having a diameter greater than that of said center portion, said sleeves being engageable with an abutment of said unit the length of which corresponds to the length of said center portion and a lever mounted on said center portion and extending through a slot of said cylinder to the exterior thereof; and measuring means for measuring the extent of such pivoting.
 4. An arrangement as defined in claim 3, wherein said support means comprises a table which is pivotable about said third axis; and said lever having a ball member exteriorly of said cylinder and engaging in a mating socket of said table.
 5. An arrangement as defined in claim 4; and further comprising adjustable abutments for adjustably limiting the axial shifting of said piston in said cylinder. 